Control system



Aug. 15, 1950 E. GROSDOFF 2,

CONTROL SYSTEM Filed April 5, 1946 4 Sheets-Sheet *1 Ez'y. I

INVENTOR. IBDR EfiRusnuFF flitorney A 15, 1950 I. E. GROSDOFF 2,519,184

CONTROL SYSTEM Filed April 5, 19-46 4 Sheets-$heet 2 &

INVENTOR. I IEuR-E. fiRusnuFF BY QQML flitorfley F F 4 4 .0 V R w t m Lew 0 n w h Eu 6 VR r 5 S m 2 a E O 4 SRSQ M B P mm ww Rm m m Aug. 15,1950 Filed Aprll 5, 1946 Patented Aug. 15, 1950 CONTROL SYSTEM Igor E.Grosdoif, Princeton,

N. J., assignor to Radio Corporation of America, a corporation ofDelaware Application April 5, 1946, Serial N 0. 659,704

2 Claims.

This invention relates to control. systems such as are adapted (l) tolimit industrial processes to a selected interval or time, (2) tocontrol a device for delivering a selected number of articles to beenclosed in a container or package, or (3) to exert a control eiiectgenerally in cases where it is desired to count or measure quantitiessuch as periods of time, numbers of objects, or the like.

In many processes such as spot welding and chemical reactions it isdesirable to have available a stop watch type of apparatus which may beutilized to terminate the process at the end of a predetermined intervalof time. In other processes such as the bottling or packaging ofarticles, it is desirable to have available means whereby selectednumbers of such articles may be delivered to the containers in whichthey are to be sold. To avoid wear and waste of energy, it is sometimesdesirable that the counting and measuring apparatus cease to operatewhen the controlled process is completed.

In accordance with the present invention, these results are achieved bymeans of a control system which includes a plurality of trigger circuitsconnected in groups each of which (1) is arranged to register a count often, and (2) is provided with means whereby any count of the group maybe selected for the purpose of exertin a control effect. These difierentgroups or decades are connected together so that one negative pulse isdelivered from a lower decade to the next higher decade each time suchlower decade completes its cycle of ten. Thus if 6.01 second is requiredto complete the cycle of the first or lowest decade, the cycle of thesecond decade will be completed in 0.1 second and that of the thirddecade will be completed in 1.6 second.

The trigger circuits of the different decades are of the type includinga pair of triodes each which (1) has its anode coupled to the grid ofthe other through a resistor shunted by a capacitor, (2) has its cathodegrounded, (3) has bias potential applied to its grid through a separateresistor, and (-i) has operating potential applied to its anode eitherthrough a separate resistor or through a separate resistor and aresistor which is common to the anodes of the two electron dischargedevices. Under these conditions, only one of the triodes conductscurrent at a time, and current conduction is transferred from one of thetriodes to the other in response (1) to the application of a negativepulse to the grid of a triode which is conducting current, (2) to theapplication of a positive pulse to the grid of a triode which is notconducting current, or (3).

to the application of a negative pulse to the common anode terminal of atrigger circuit having a resistor common to both its anodes. In allcases, the control pulses are applied to the input terminal of thelowest decade.

The selector for producing a desired control effect in response todifferent numbers of pulses applied to the input termina1 of the lowestdecade may be either in the form of a separate selector switch for eachdecade or in the form of a single selector switch for all the decades.-In either case, (1) the application of pulses is started by completionof a circuit between the source of pulses and the input of the lowestdecade, and (2) this circuit is interrupted and a control pulse isapplied to the controlled device when a number of input pulsespredetermined by the setting of the selector switch or switches has beenapplied to the input terminal of the lowest decade.

The principal object of the invention is the provision of an improvedcontrol system and method of operation whereby a control pulse isproduced in response to any desired number of input pulses. Importantobjects of the invention are the provision of a control system which isadapted to limit an operation to a selected time interval, and theprovision of a control system which is adapted to respond to a selectednumber of pulses for producing a measuring or counting effect.

The invention will be better understood from the following descriptionconsidered in connection with the accompanying drawings and its scope isindicated by the appended claims.

Referring to the drawings:

Fig. l is a wiring diagram of the control circuits of one form of theinvention, the counters or decades being shown as blocks bearing aswitch blade and fixed contacts numbered ii to 9.

Fig. 2 is a wiring diagram of one form of counter or decade.

Fig. 3 illustrated a modified form of control circuit, and

Fig. l is a wiring diagram of a preferred form of the invention whichhas the advantage that it is simpler and involves fewer parts than themodifications of Figs. 1 to 3.

The computer of Fig. l is shown as including three chains ofmulti-vibrators or trigger circuits Zil, 2i and 22. These chains aredesigned in manner well known in the art so that the chain 22 completesits cycle in 0.01 second, the

chain 2! completes its cycle in 0.1 second and the chain 2 3 completesits cycle in 1.0 second. As a result, each rnultivibrator unit of thechain or decade 22 represents 0.901 and those of the decades 2! and 2%represent respectively 0.01 second and 0.1 second. These decades are sointerconnected that each time a lower decade completes its cycle, itdelivers one pulse to the :inputsterminal of the next higher decade. Forexample, the three decades of Fig. l are capable of measuring a timeinterval of 1.000 second or any shorter time interval down to 0.001second. This time of time computing device is well known and readilyunderstood without detailed explanation.

The present invention relates to theme of such a computer to select orindicate different intervals of time dependent on the setting ofthe-computer. To this end, a switch 23 is provided for starting andstopping the time measuring operation, the stopping of the operationbeing effected through a nrultigrid tube 24 having grids '25, 2 6 and 21a-cathode 2-8, and an anode 29 connected to a positive terminal througha resistor Associated with the decade 22 is a lead 3| which is coupledthrough a capacitor 32 to the grid 21 and'is connected to a switch bladewhich is arranged to engage fixed contacts e, i, *2, 3, 4, '5, '6, 'l, 8and 9 for connecting the lead3l to any one pf themultivibrator units ofthe chain or decade 22. If the blade is in engagement with the fixedcontact i, apositive pulse is applied to the grid 27 each time a countis registered on the corresponding multivibrator of the decade.Similarly the decades 2i and 26 are provided respectively with 'leads 33and 35 and with fixed switch contacts numbered in the same manner asthose of the decade 22, the lead 33 being connected through a resistor34 to the grid {25 and the Plead 35 being connected through aresistor 36tothegrid-ZB.

The tube "2d takes-current only when all three of ,its grids are mademore positive. This can be made 'to'occur in response to the applicationof any desired number of pulses to the decades Z-2i--22. i or example,closure of the switch for decade 22, the switch Bof decade 2! and theswitch of decade means that all three grids will be positive only at aperiod of 0.567 second after the time measuring operation is started. Atthe end of this period, the tube 2Q draws current through a resistor '30thereby producing a negative pulse at the grid of the switch 23 andoperating this switch to interrupt the application of input pulses froma source 38 through a control tube 39 to the input of the decade 22.

The switch 23 "includes a pair of trigger circuits 4t and 1, and aduotriode d2 which (1) is provided with aresistor common to its twoanodes and (2) has its anodes-connected through a resistor M to thefirst control grid c5 of the control tube 39. 'Bias potential is appliedfrom a lead 48 through resistors l"! and d8 respectively to the lefthand grids 59 and 5?) of the trigger circuits so and and from the lead46 through a reset switch 5! and resistors 52 and "53 respectively tothe right hand grids 54 and 36 of the trigger circuits Ail and il.Opening and closing the switch 51 puts the trigger circuit units it and$1 in a standby condition with Current conduction in their right handanodes as indicated by the arrows. Under these conditions, the grid '55of the duotriode 42 is more positive, the grid 55 of the duotriode 42 ismore negative, and sufiicien-t current flows in 4 the resistor 43 tomaintain the grid of the control tube 39 at such a potential that nopulses are supplied from the source 33 through the control tube 39 tothe decade 22.

The supply of pulses to the decade 22 is started by closing and openingswitch 5? which functions .to ,transier current conduction to the lefthand anode of the unit :20 thereby making the grid more negative,reducing the current of the resistor 43 and applying to the grid 35 amore positive potential such that oscillations are transmitted throughthe control tube 39 to the decade 22..

'With the switch blades of the decades 20, 2! and 22 set .asillustrated, the tube 24 is biased off for any number of input pulsesless than 567. When the number of input pulses reaches 567, grids 25 and2B are positive by conduction and a positive pulse is applied to thegrid 2? through the capacitor 32. As a result, the tube 243 drawscurrent through the resistor 36, a negative pulse is applied through thelead 3? to the grid 36, current conduction oes to the left hand anode ofthe unit 4!, the grid 56 is made more positive, more current is drawnthrough the resistor :33, and the potential of the grid 45 is madesufficiently negative to stop the supply of pulses through the controltube '39 "to the decade 29.

The decades 28, 25 and 22 of Fig. 1 may be i of various types such as(1) that illustrated by Fig. '2 wherein a dillerent trigger circuit isprovided for ,each digit of the decade or (2) those illustrated by lwherein a smaller number of trigger circuits are combined with aresistance network to provide the required dig-ital representation.

For convenience in understanding there *is illustrated in Fig. 2 adecade which (1) includes ten trigger circuit units 58 to 67 which areconnected through a lead 555 in a closed loop or chain and (2) may betaken as representative of the decades 2?), 2i and22 of Fig. l.

Operating potential is applied from a terminal '59 to the anodes of theunits '58 to 6'! through separate resistors cc to '59, bias potential isapplied to their grids from leads and 3! through resistors d2 to mi, anda reset switch N32 is provided for putting the decade in a standbycondition with current conduction in the anode resistors '50, 513 65,5?, 59, H, l3, l5, Ti and 19. Input pulses are applied to the left handgrids of the various units through a lead Hi3 and the capacitors to H3.It will be noted that the left hand anodes of the units 58 tol are eachcoupled to the left hand grid of the next successive unit through acapacitor l M and that the triodes of each unit have their grids andanodes cross-connected as previously explained so that only one triodeof the unit conducts current at a time.

The operation of such a decade as this is too well known to requiredetailed explanation. It is based on the fact that (1) only one of theunits 58 to 6'! is conducting current through its left hand anode at anygiven time, (2) all the other units are insensitive to a negative pulseapplied through the terminal [63 and the capacitors I04, ['05, etc., (3)such a negative pulse functions to transfer current conduction from theleft anode to the right anode of the one :unit, and (4) there is appliedfrom the left anode of the one unit through a capacitor M4 to the lefthand grid of the next successive unit a positive pulse whereby currentconduction is transferred from the right to the left anodeo'f this nextsuccessive unit which is thus made sensitive to the next negative pulseapplied from the terminal I 03 through the corresponding capacitor tothe grid of the conducting triode. This process continues throughout thedecade, the cycle of operation being repeated over and over again solong as negative pulses are applied to the terminal I03.

With the setting of the selector switch as illustrated in Fig. 2, apositive pulse is applied through the lead 3| and the capacitor 32 tothe grid 21 (see Fig. 1) each time current conduction is transferredfrom the left to the right anode of the unit 64. Each time the decade 22completes its cycle of ten counts, a positive pulse is applied through acoupling capacitor II to the grid of a triode I I6 and a negative pulseis applied from the terminal III to the pulse input terminal of thedecade 2!. The decade M is similarly connected to the decade 20. Thuswith the three selector switches set as illustrated in Fig. 1, all threegrids of the tube 24 are made positive only when current conduction istransferred from the left to the right anode (1) of unit 64 of decade22, (2) of unit 63 of decade 2I, and (3) of unit 52 of decade 26. Thiscorresponds to a count of 567 pulses. It is obvious that any otherdesired number of pulses may be selected to terminate the supply ofpulses and to energize a control device connected to the terminals III]and I 26 of Fig. l.

The modification of Fig. 3 is similar to that of Figs. 1 and 2 with theexception that difierent means are provided for applying the stop signalto the switch 23. In this case, the pentode 24 of Fig. 1 is replaced bya triode I2I. Grid bias potential for the triode I2I is derived from aresistor I22 which has its high voltage terminal connected to the anodesof diodes I23, I24 and I25. The cathodes of these diodes are connectedto the selector switch blades of the decades 22, 2| and 20 respectively.

With the three selector switches in their illustrated positions, allthree diodes draw current only when current conduction is in the righthand anodes of the unit 64 of decade 22, the unit 33 of decade 2! andthe unit 52 of decade 23. When all three diodes conduct current, thegrid of triode I2I becomes suiiiciently negative to stop current throughthe anode resistor I 26, and a positive control pulse is delivered tothe lead 31 of the stop switch 23 (Fig. l) and to any other controlleddevice which may be connected to this lead.

The modification of Fig. 4 is preferable to those previously describedfor the reason that it involves fewer trigger circuits and is controlledby a less complicated selector mechanism, It is distinguished by thefact that (1) the decades consist of only four trigger circuit units sointerconnected that they function to deliver one output pulse inresponse to ten input pulses, (2) a single selector mechanism isprovided for all the decades, and (3) the whole control system operatescontinuously to deliver a positive output pulse in response to inputpulses, 12 input pulses, 25 input pulses, as input pulses or 100 inputpulses dependent on the setting of this single selector mechanism. Thedecades of this modification are likethose disclosed in my copendingapplication Serial No. 580,446, in that they include a feedbackconnection from the left hand anode of the fourth trigger circuit of thedecade to the right hand grid of the second trigger circuit and from theleft hand anode of the third trigger circuits to the right hand grid ofthe second trigger circuit so that an output pulse is delivered to thenext decade only when ten input pulses have been applied.

The control system of Fig. 4 is illustrated as including two decades I28and I29. The decade I 28 includes four trigger circuit units I33 to I33which are of a well known type having operating potential applied totheir anodes from a socket power unit I34 through lead I35, a resistor I36 common to the two anodes or the unit and resistors I31 and I38 whichare individual to the separate anodes. Grid bias potential is appliedfrom the socket power unit I34 through leads I35, I48 and MI andresistors I42 and I43. A reset switch I44 connected between the leadsI49 and MI is opened and closed to put the decade I28 in a standbycondition with current conduction in the resistors I33. Negative inputpulses are applied through a coupling capacitor I45 to the common anodeterminal of the first or lowest order unit I33 of the decade. Suchnegative input pulses are derived through a switch I46 and a triode I41which has its anode I48 coupled through a capacitor I49 to the grid I55of a triode I 5| so that the current of the triode I5I is increased inresponse to each input pulse and a negative pulse is produced at theterminal I52 of the resistor I53.

The decade I29 is similar to the decade I28.

In both cases the anode I54 of the lower order' unit is coupled througha capacitor I55 to the common anode terminal of the next higher orderunit as is usual in counters of this type. The output terminal of thedecade I28 is coupled to the input terminal of the decade I23 through acapacitor I53 so that one pulse is delivered to the decade for every tenpulses applied to the input of the decade I28.

The left hand anode of the unit {33 is com nected through a feed-backconnection I6IJ-I5I to the right hand grid of the unit I32 and thelefthand anode of the unit I33 is similarly connected to the right handgrid of the unit I3I through a feedback connection USS-I33. Thecorrespond-- ing units of the decade I 29 are similarly interconnected.With these connections, each decade of four triodes delivers one outputpulse in response to ten input pulses.

Positive output pulses are delivered from the common anode terminal I65of a pair of triodes I66 and I61 which are connected to the high voltageterminal I35 through a resistor I68. So long as the triodes I66 and I61take current, the output terminal I56 is more negative. When the currentdrawn through the resistor I68 decreases, the terminal I56 is made morepositive. The amount of current drawn through the resistor I 68 isdetermined by the potential applied to the grids I18 and H! of thetriodes I65 and I61. Such potential is controlled by a selector switchI12 which is connected to the decades I28 and I29 so that minimumcurrent is drawn through the resistor I68 only in response to a count of10, 12, 25, 50 or 100 input pulses.

The selector I12 includes (1) a conductive segment I13 having a contactI14 which is arranged to engage a plurality of .fixed contacts I15 toI18 as segment I13 is rotated around its axis, 2) a conductive segmentI19 having a contact I86 arranged to engage a plurality of fixedcontacts I8I to I as segment I19 is rotated together with the segmentI13, and (3) a pair of brush contacts I86 and I81 through which thesegments I 13 and I19 are connected respectively pulse in .response toany one of a lected groups of input pulses. Such :control assures to thecontrol grid of the triode I61 and to the grid of the triode I66.

With the selector I12 in its illustrated posi tion, the grids I and I'llare both connected to the right hand anode of unit IzB-I of the decadeI129. .Since current conduction is transferred to the right hand anodeof the unit I9I only in :response to each 100 input pulses, it isapparent that a positive pulse be delivered through the capacitor I92tothe output terminal I56 for each 10.0 input pulses.

With the selector in a position such that the contact 114 engages thecontact I and the contact I 8l] engages the contact I82, (1) a negativepotential is applied from the right anode of the unit I33 throughcontacts I14, I15 and I86 to the grid I10 and (2) a negative potentialis applied from the left anode of the unit I00 and the left hand anodeof the unit I88 through contacts m2, I80 and I81 to the grid I'll. Sincethis condition of the decades represents a-count of 50 input pulses, itfollows that a ositive pulseis delivered at the terminal I56 for each 50input pulses.

When the selector I12 is in a position such that the contact flie'ngagesthe contact I16 and the contact I20 engages the contact I83, (1) thegrid I10 is connected through contacts 186, I'I l and I16 to the lefthand anode of the unit I32 and the left hand anode of the unit I30 andis made negative in response to a count of input pulses and ('2) thegrid IEI is connected through contacts I81, I80 and I83 to the left handanode of the triode tube unit I89 which is pulses may provide a measureof time, a uneasure of numbers of articles or the like depending on theuse made of the invention.

I claim as my invention:

1. The combination of firstand second counters each having an input leadand an output lead and each including four trigger circuits sointerconnected that its cycle .of operati n is completed inresponse tothe application of ten pulses to its input lead, means coupling theoutput lead of said first counter to the input lead of said secondcounter, unitary switching means connected to said first and secondcounters to select from said counters pairs of potentials each pair ofwhich is more negative only in response "to the application or "adifferent predetermined number or pulses to the input lead of saidfirstcounter, and means responsive to each of said pairs 101E morenegative potentials for producing a single output pulse.

- 2. The combination of first and second counters each having an inputlead and an output lead and each includingfour trigger circuits sointerconnected that its cycle of operation is completed in response tothe application of ten pulses to its input lead, means coupling theoutput lead of said first counter to the input lead of said secandcounter, unitary switching means connected also negative at the count of25 input pulses. A

positive output pulse is therefore delivered at the terminal B inresponseto 25input pulses.

When the selector 'IIZ is in a position such that the contact I" engagesthe contact I" and the contact I engages the contact I84, the grid I10is connected through contacts I86,- I'M and IT! to the left hand anodeof the unit I3I and the grid I'll is connected through contacts I81, I80and I84 to the left hand anode of the unit I88 so that both grids aremade negative in response to a count of 12 input pulses and a positivepulse is delivered at the output terminal I55. When the selector I12 isin a position such that the contact I14 engages the contact I18 and thecontact I80 engages the contact I85,

the grid I153 is connected-through the contacts I86, 114 and M8 to theright hand anode of the unit I33 and the grid I'II is connected throughthe contacts I 31, I80 and I85 to the left anode of the unit I88 so thatboth grids are made negative in response to ten input pulses and apositive output pulse is delivered at the output terminal .I 56.

The output pulse delivered at the terminal 456 obviously may be utilizedfor a variety of purposes such as moving an empty container into aposition to receive a counted number of articles or the like. The inputpulses applied through the capacitor I45 may be produced by sucharticles obstructing the light applied to a photoelectric cell as theydrop into the conr tai-ner. Other uses vfor the control system e111 beapparent to those skilled in the art.

What the invention provides is a control system which maybe adjusted toproduce a control number of seto said first and second counters toselect from said counters pairs of potentials each pair of which is morenegative only in response to the application of a difierentpredetermined number of pulses to the input leadof said first counter,and a pair of triodes having a common anode resistor and having theirgrids connected -to respond to said pairs of potentials efer-producing apositive output pulse at their common anode terminal. Y

IGOR E. GROSDOFF.

asrsusncns CITED The following references are of record in the file ofthis patent.

UNITED STATES Pi'iTENTS Nature: vol. 125, No. 3156, April 26,1930,Method of Registering Multiple Simultaneous impulses of Several GeigersCounters by Rossi.

Review of Scientific Instruments: vol. 12, February 1941, The IntervalSelector. by Roberts.

Electronics: October 1942, Radiation Instru ments Using Geiger MullerTubes by Weisz.

Electronics: June 1944, ,A Four-Tube Counter Decade by John T. Potter.

